This invention relates generally to the field of gathering of oceanographic data, and more particularly to an improved buoy system for obtaining a vertical profile of oceanic conditions from the surface to a predetermined depth below the surface.
There has been a long standing desire by ocean scientists to measure parameters such as water temperature, as a function of depth from the surface to a depth of, say, 1000 meters, over a substantial period of time. Several approaches have been used including measurements made from the surface by means of thermistor arrays incorporated in or attached to buoy mooring lines, or by sensing probes lowered by a programmed winch in a moored surface buoy. Such systems are particularly vulnerable to wave action damage to the buoys, to mooring cables, and to associated sensor arrays. The damage to the cables and arrays has been particularly troublesome and has been in the form of breaks in lines and conductors due to jerking motions of the supporting buoy and in the form of disabling snarls and tanglements.
Subsurface techniques have included self-recording arrays attached to subsurface moorings and traveling programmed probes or instrumentation vehicles designed to rise periodically from a predetermined subsurface level, through the zone being profiled, to the surface and return to the subsurface level. Data accumulated before or during the travel is telemetered to a receiving station while the probe is at or very near the surface. Examples of devices of the latter type are found in U.S. Pat. No. 2,422,337 of C. Chilowsky, U.S. Pat. No. 3,628,205 of B. J. Starkey, et al, and U.S. Pat. No. 3,936,895 of H. R. Talkington.
Such prior art traveling devices are powered by electrical batteries or by compressed or chemically generated gas either for operating winches or changing the displacement, and hence the buoyancy, of the probe. These systems have generally been unduly complex, inefficient, expensive, and unreliable in operation. Those using winches to control movement of a buoyant traveling probe are subject to failure by reason of mechanical breakdown, fouling by marine growth, or insufficient supply of power. Those relying on changes in buoyancy of the traveling probe that is tethered to a sub-surface moored buoy are also prone to failure due to entanglement of the probe tether with the subsurface buoy and its mooring cabe due to currents and deep wave action.
In order to minimize the effective work that must be done in a complete cycle of operation of a traveling probe device, it is desirable in some instances to have the power source, i.e. electrical batteries or compressed gas tanks, located in the non-traveling portions of the system. However, in traveling probe devices wherein the probe tether slides between stops on the subsurface buoy mooring cable, as in the Talkington patent, the complete power supply must be carried in the probe vehicle because of inability to transmit electrical power or pressure fluid, from the subsurface buoy or mooring, through the sliding coupling and tether to the probe. Similar transmission problems arise when the tether is articulated and carries a pendant weight as also disclosed in the Talkington patent.